(1) Field of the Invention
The invention relates to permanent magnet rotors for electronically commutated direct current motors with a shaft and a laminated rotor core carried by the shaft.
(2) Description of Related Art Including Information Disclosed Under 37 CFR §1.97 and §1.98
From US 2007/004009 A2, a generic rotor is known, in which, in an inner region of the laminated rotor core, which is radial to the permanent magnet plates, there are additional recesses, which are open to the recesses for the permanent magnet plates. Spring elements, which exert an outward radial force on the permanent magnet plates, are inserted into each of these additional recesses. This known solution has the disadvantage that the permanent magnet plates are not clearly fixed in the tangential direction by the spring force; as a result, the magnets may move under external load within the recess at right angles to the spring force. The springs furthermore have no effect on imbalances, which may possibly arise. An additional disadvantage exists therein that, due to the additional recess, the magnetic resistance of the magnetic circuit is increased because the recess is arranged in the main flux region.